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This invention relates generally to exchanging information in a client-server computer environment. More particularly, this invention relates to an improved technique for responding to information requests at a server computer.
Client-server computer networks are well known. The most prominent example of a client-server computer network is the World Wide Web of computers. In a client-server computer network, a server computer receives a request for information from a client computer. Web server software operating on the server computer typically retrieves the requested information from a file stored on a permanent storage device and transmits the file over the network to the client computer that requested the information. The web server software is generally not written using an object oriented programming language. Thus, it is not easily extended to provide new functionality. Given the dynamic nature of today""s software marketplace, a product""s lack of flexibility and extendibility can seriously hinder the marketability of the product.
Current web server software can generate a file dynamically in response to a request from a client computer. Typically, the web server receives the request and then forks a Common Gateway Interface (CGI) process to dynamically create the file. Once the file has been created, the web server software transmits the file back to the client computer. Unfortunately, it is computationally expensive to fork a process each time dynamic information needs to be generated.
In view of the foregoing, it would be highly desirable to provide a web server which dynamically generates information in response to a client computer request, but which does not incur a process start-up expense while generating the dynamic information. Further, it would be highly desirable to provide an object oriented web server environment that is flexible and extendible.
The invention includes a method and apparatus for operating a local server computer of a client-server network. The invention includes a technique to receive a request from a client computer of the client-server network. A determination is made whether the request requires dynamically generated information from a servlet object of the client-server network. If so, a specified servlet object corresponding to the request may be uploaded from a remote server computer of the client-server network. The specified servlet object is then executed to obtain dynamically generated information corresponding to the request.
The servlet objects of the invention provide an object oriented web server environment which is flexible and extendible. The client-server network of the invention is populated with the servlet objects. The servlet objects operate in a continual loop until invoked. Thus, there is no startup overhead associated with execution of the servlet objects. By observing a common applications program interface, the servlet objects can run in any server environment. A feature of the invention allows untrusted servlet objects to be executed in a secure area, with the dynamically generated information being passed from the secure area into the remaining server environment.